Remove IEditorFactor::open implementation with a warning

Looks very much like the current IDocumentFactory / IEditorFactory
set up does not make much sense. Should be cleaned up in a follow-up
commit.

Change-Id: I000b68fe6b6d75add713866818711545b41dfe23
Reviewed-by: David Schulz <david.schulz@digia.com>

src/plugins/coreplugin/editormanager/ieditorfactory.cpp

@@ -29,11 +29,12 @@
 
 #include "ieditorfactory.h"
 
-#include "ieditor.h"
-#include "editormanager.h"
+#include <utils/qtcassert.h>
 
-Core::IDocument *Core::IEditorFactory::open(const QString &fileName)
+Core::IDocument *Core::IEditorFactory::open(const QString &)
 {
-    Core::IEditor *iface = Core::EditorManager::openEditor(fileName, id());
-    return iface ? iface->document() : 0;
+    qWarning("This should never be called, use IEditorFactor::createEditor, "
+             "or EditorManager::openEditor instead!");
+    QTC_CHECK(false);
+    return 0;
 }

src/plugins/coreplugin/editormanager/ieditorfactory.h

@@ -44,7 +44,7 @@ public:
     IEditorFactory(QObject *parent = 0) : IDocumentFactory(parent) {}
 
     virtual IEditor *createEditor(QWidget *parent) = 0;
-    virtual IDocument *open(const QString &fileName);
+    virtual IDocument *open(const QString &);
 };
 
 } // namespace Core